Video "Flashing Quantum Points"
| Image data | |
| Image size: | 5 x 5 µm |
| Temperature: | app. 50 K |
| Number of points: | 128 x 128 in x,y; 1024 in Z (Wavelength) |
| Total data size: | 33.5 MB |
| Spatially integrated opt. spectrum: |  |
Coupling of quantum dots: Quantum physics in
action
The video shows the wavelength dependent emission of InP (Indiumphosphid) quantum dots (embedded in GaInP, substrate GaAs). The sample comes from 4. Physikalischen Institut of Universtität Stuttgart. At the edge of the emission spectrum only a few quantum dots are emitting, which looks like a random flashing at different locations. When the wavelength comes close to the emission maximum, more and more quantum dots start to emit. At the emission maximum, it is no longer possible to separate the individual emitting quantum dots, as their density is too large and the resolution capability is no longer sufficient. When the emission maximum is left, the density is reduced, so that at the other edge it is again possible to identify individual quantum dots.
If one looks very closely it is possible to see that at the long wave end of the emission spectrum the emission is seen as oblong forms, in contrast to the short wave end of the spectrum, where the forms are small and round. The oblong emission forms originate from coupled quantum dots. Is is very seldom possible to observe such effects directly.